Designing sustainable recreational trails

August 2012 » Columns » CE + GIS INTERSECT
Janet Jackson, GISP; Barb Oslund, P.E.

GIS perspective
Jackson: Creating a map of horse trails can be serious GIS work. It's serious because there are so many critical variables needed to make the map accurate and complete, and because it's challenging to create a map display that is easy to understand for a wide variety of users.

Land managers, facility maintenance personnel, and planners are just a few of the groups that rely on the accuracy of the GIS map details to help them plan, administer, and properly maintain horse trails. Specific layers such as aerial photos, land contours, water sources, and public land and road intersections need to be displayed and labeled clearly. Having all this information in one place – a GIS – makes it easy and efficient to print out different scales of details as needed by each professional.

Safety for the riders, horses, and those associated with the horse trail program are high priorities. The GIS maps should clearly display all points of safety concerns, such as steep slopes, rocky trails, stream and road crossings, areas where animal sightings have taken place (if known), and the quality of cell phone coverage along the trails. Local emergency responders also should have access to an accurate and complete GIS map that shows and labels important trail information so, in the event of an emergency, the horse and rider can be located quickly.

No matter what type of map is needed, remember to keep your unique audience in mind as you create it. That way it doesn't matter if you're a serious GIS user or just horsing around with the software to create what you need, your GIS map will be a valuable resource for everyone.

Janet Jackson, GISP, president of INTERSECT (www.intersectgis.com), a GIS consulting firm, travels the country talking about the importance of intersecting GIS with other professions to create effective solutions for clients. She can be contacted at jjackson@intersectgis.com.

Engineer perspective
Oslund: You may never look at a trail the same way again when you realize how engineering design is being applied to make recreational trails sustainable – low maintenance, protective of natural resources, and enjoyable for users. Though applicable to any natural surface trail, this concept has particular importance for horseback riders and mountain bikers, whose trail use can significantly displace and compact native soil.

Water, steep slopes, and organic soils are the biggest enemies of natural surface trails. Keeping water off the trail by directing sheet flow across the trail surface (i.e., perpendicular to the alignment) is key to minimizing channeling and erosion. To facilitate this, the trail alignment should never follow the fall line (i.e., straight down a hill, channelizing water) and generally shouldn't be steeper than 50 percent of the location's side-slope. A trail tread should consist of the mineral layer of soil and be constructed with an out-slope. Wetlands, floodplains, and other areas of organic-rich soil should be avoided except where stream crossings are necessary.

GPS and GIS are indispensible to achieve sustainable trail design principles. Even the recreational-grade GPS, coupled with publicly available topographic and soil survey GIS files, can be used effectively to map problematic trail alignments, evaluate re-routes, avoid property encroachments, incorporate desirable natural features, avoid hazards and sensitive/protected areas, and plan new trail systems.

Soil survey GIS files available from the USDA-NRCS provide a good overview of soil types, surface water, and wetland areas. County GIS files provide parcel data, and often have small interval topography and other important data such as stream buffers and flood zones, with accuracy levels adequate for a typical trail project. The GPS is used to field-collect alignment coordinates that are then exported into GIS with the relevant data layers. Alternatively, the GIS maps and data can be used to digitize a new trail route, which is exported to the GPS and used for field location. Finally, great user maps and applications can be created to minimize trail users getting lost and allow them to be found in emergencies.

As a lifelong equestrian, trail rider, and outdoor enthusiast, Barb Oslund, P.E., became involved with sustainable trail design after seeing horseback riding restricted because of badly designed trails and natural resource damage.
 

Barb Oslund, P.E., with a 25-year consulting career primarily in environmental remediation, provides trail and nutrient management consulting services on behalf of the non-profit NC Horse Council. She can be contacted at bloqresources@gmail.com


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